VoNR – Voice over New Radio
VoNR (Voice over New Radio) is the 5G equivalent of VoLTE. It uses the same IMS core for call signalling and control but delivers voice packets over the 5G New Radio (NR) air interface on a 5G Standalone (5G SA) network. VoNR supports the EVS codec for super-wideband and fullband audio quality. It requires 5G SA deployment – not 5G NSA.
VoNR vs VoLTE
| Feature | VoLTE (4G) | VoNR (5G SA) |
|---|---|---|
| Network | 4G LTE / EPC | 5G NR / 5GC |
| Signalling | SIP via IMS | SIP via IMS (same) |
| Primary codec | AMR-WB (HD Voice) | EVS (Super-WB / Fullband) |
| Audio range | 50 Hz – 7 kHz | Up to 20 kHz (fullband EVS) |
| Latency | Typically 50-100ms | Lower – 5G NR URLLC capability |
| Network slicing | No | Yes – dedicated voice slices possible |
| UK availability | Live on all 4 networks | Limited – tied to 5G SA rollout |
Why VoNR requires 5G SA
The majority of UK 5G deployments are 5G Non-Standalone (NSA). In 5G NSA, the 5G NR radio provides additional downlink and uplink capacity, but the control plane runs on the 4G LTE core (EPC). Voice calls on a 5G NSA phone use VoLTE on the 4G bearer – not VoNR.
5G Standalone (SA) replaces the 4G core with the 5G Core (5GC), which natively integrates with the IMS for VoNR delivery. Only 5G SA networks can deliver true VoNR calls.
UK operators are building out 5G SA infrastructure. Consumer VoNR availability remains limited, but enterprise VoNR – particularly via network slicing for organisations with specific QoS requirements – is an emerging use case.
EVS codec – beyond HD Voice
VoNR introduces the EVS (Enhanced Voice Services) codec as the preferred voice codec. EVS is defined in 3GPP TS 26.441 and supports multiple operating modes:
- Narrowband – 50 Hz to 8 kHz at 7.2 kbps – comparable to AMR-WB
- Wideband – 50 Hz to 8 kHz at higher quality and better packet loss resilience
- Super-wideband – 50 Hz to 14.4 kHz – noticeably richer than AMR-WB
- Fullband – 20 Hz to 20 kHz at 9.6 to 128 kbps – CD-quality voice
EVS also provides significantly better performance in packet loss conditions than AMR-WB, making it more resilient in challenging radio environments.
VoNR and IoT
For IoT applications, VoNR on 5G SA networks opens up voice-over-5G capability for devices embedded in 5G-connected industrial equipment. Network slicing allows an operator to guarantee specific QoS parameters for a voice slice – relevant for applications where audio quality and latency are mission-critical.
In practice, most IoT voice applications in the UK will remain on VoLTE (4G) for several years while 5G SA coverage expands. Planning for VoNR compatibility now – choosing modules that support 5G SA and IMS – avoids a hardware replacement cycle when 5G SA coverage becomes viable.